Low-travel key mechanisms with butterfly hinges

Abstract

A key mechanism can include one or more butterfly hinges. Each butterfly hinge includes a double wing design operative to move between a depressed position and non-depressed position. Hinged coupling mechanisms couple respective arms of the wings together.

What is claimed is: 
     
       1. A key mechanism, comprising:
 a keycap; 
 a substrate; and 
 a butterfly hinge movably coupling the keycap to the substrate, the butterfly hinge comprising:
 a first wing; 
 a second wing; and 
 a living hinge flexibly coupling the first wing to the second wing; wherein 
 
 the first wing comprises a first arm extending towards the second wing; 
 the second wing comprises a second arm extending towards the first wing; and 
 the living hinge joins an end of the first arm to an end of the second arm. 
 
     
     
       2. The key mechanism of  claim 1 ,
 the first arm and the second arm each comprise retention features; and 
 the living hinge conforms to the retention features to retain the living hinge to the first arm and the second arm. 
 
     
     
       3. The key mechanism of  claim 2 , wherein:
 the first wing and the second wing comprise a first polymer; and 
 the living hinge comprises a second polymer that is more flexible than the first polymer. 
 
     
     
       4. The key mechanism of  claim 3 , wherein the second polymer is an elastomer. 
     
     
       5. The key mechanism of  claim 3 , wherein the retention features comprise protrusions. 
     
     
       6. The key mechanism of  claim 1 , wherein:
 the living hinge is a first living hinge; 
 the key mechanism further comprises a second living hinge; 
 the first wing comprises a third arm extending towards the second wing; 
 the second wing comprises a fourth arm extending towards the first wing; and 
 the second living hinge joins an end of the third arm to an end of the fourth arm. 
 
     
     
       7. A hinge mechanism for an input key, comprising:
 a first hinge member defining a first arm; 
 a second hinge member defining a second arm and positioned opposite the first hinge member; and 
 a flexible member at least partially encapsulated in the first arm and at least partially encapsulated in the second arm to couple the first arm to the second arm and to substantially synchronize the movement of the first and second hinges. 
 
     
     
       8. The hinge mechanism of  claim 7 , wherein:
 the hinge mechanism is incorporated in a keyboard mechanism comprising:
 a keyboard base; 
 a keycap; and 
 a dome switch coupled to the keyboard base below the keycap; 
 
 the hinge mechanism is coupled to the keyboard base and the keycap and movably supports the keycap relative to the keyboard base; and 
 the flexible member is formed from a metal. 
 
     
     
       9. The hinge mechanism of  claim 8 , wherein:
 the keyboard mechanism comprises a plate coupled to the keyboard base; 
 the first and second hinges each comprise a pivot pin; and 
 the respective pivot pins are captured between the keyboard base and respective portions of the plate. 
 
     
     
       10. The hinge mechanism of  claim 7 , wherein:
 the flexible member defines:
 a first retention feature; and 
 a second retention feature; 
 
 the first arm engages the first retention feature, thereby retaining the first arm to the flexible member; and 
 the second arm engages the second retention feature, thereby retaining the second arm to the flexible member. 
 
     
     
       11. The hinge mechanism of  claim 7 , wherein:
 the first hinge member further comprises:
 a third arm; and 
 a first cross-piece coupled to an end of the first arm and an end of the second arm; and 
 
 the second hinge member further comprises:
 a fourth arm; and 
 a second cross-piece coupled to an end of the second arm and an end of the fourth arm. 
 
 
     
     
       12. The hinge mechanism of  claim 11 , wherein:
 the first arm, the third arm, and the first cross-piece define a first U-shaped portion of a cavity between the first and the second hinge members; and 
 the second arm, the fourth arm, and the second cross-piece define a second U-shaped portion of the cavity between the first and the second hinge members. 
 
     
     
       13. The hinge mechanism of  claim 12 , wherein:
 the hinge mechanism is incorporated in a keyboard comprising a dome switch; and 
 the dome switch is positioned in the cavity between the first and the second hinge members. 
 
     
     
       14. A method of forming a hinge mechanism, comprising:
 forming a first wing comprising:
 a first cross-piece; 
 a first arm extending from a first end of the first cross-piece; and 
 a second arm extending from a second end of the first cross-piece; 
 
 forming a second wing comprising:
 a second cross-piece; 
 a third arm extending from a first end of the second cross-piece; and 
 a fourth arm extending from a second end of the second cross-piece; and 
 
 forming a living hinge coupling an end of the first arm to an end of the third arm. 
 
     
     
       15. The method of  claim 14 , wherein the operation of forming the living hinge comprises:
 positioning the first wing and the second wing in a mold; and 
 injecting a flexible material into the mold and against the end of the first arm and the end of the third arm. 
 
     
     
       16. The method of  claim 15 , wherein:
 the end of the first arm and the end of the second arm each comprise a retention feature; and 
 the operation of injecting the flexible material into the mold comprises at least partially encapsulating the retention features in the flexible material to lock the flexible material to the first arm and the second arm. 
 
     
     
       17. The method of  claim 14 , wherein:
 the living hinge is a first living hinge; and 
 the method further comprises forming a second living hinge coupling an end of the second arm to an end of the fourth arm. 
 
     
     
       18. The method of  claim 14 , wherein the operations of forming the first wing and the second wing comprise injecting a polymer material into a mold. 
     
     
       19. The method of  claim 18 , wherein:
 the method further comprises placing a metal insert into the mold prior to injecting the polymer material into the mold, wherein the metal insert forms at least a portion of the living hinge; and 
 the operation of injecting the polymer material into the mold encapsulates a first portion of the metal insert in the first arm and a second portion of the metal insert in the third arm.